Forensic Trauma 1 + 2 Flashcards
What is the definition of an injury?
‘Damage to any part of the body due to the application of mechanical force’
What is an important factor to consider when thinking about the mechanism of injury?
The area over which the force was applied - a smaller area with a similar force will result in more damage
Mechanism: what is compression?
Squashing
Mechanism: what is traction?
Stretching
Mechanism: what is torsion?
Twisting
Mechanism: what is tangential?
Shearing
How are injuries classified?
- Appearance/method of causation
- Abrasion, contusion, laceration etc
- Manner of causation
- Suicidal, accidental, homicidal
- Nature of injury
- Blunt force, sharp force, explosive
What is a contusion?
Bruises: blood vessels under skin burst
What is an abrasion?
Graze/scratch: Scraping of skin surface
What is a laceration?
Cut/tear: Tear/split of skin due to crushing force
What causes tramline bruises?
- Long cylindrical/square object
- As object hits skin it pushes blood to the side and bursts vessels at edge
- This creates two lines of bruise
What are common bruises to find in strangulation situations?
Fingertip bruises
What are some factors affecting the prominence of the bruises?
- Skin pigmentation
- Depth and location
- Fat: more subcutaneous fat will bruise easier
- Age: children/elderly
- Resilient areas: buttocks, abdomen – bruise less easily with given impact than areas with underlying bone which acts as an anvil with skin between bone and inflicting object
- Coagulative disorders: alchoholic
What are present in laceration wounds that differentiate them from incised wounds?
They are known as ‘bridges’, see image
What is an incised wound?
- Superficial sharp force injury caused by slashing motion
- Longer on the skin surface than it is deep
What is a stab wound?
- Penetrating injury resulting from thrusting motion
- Wound depth greater than length on the surface
What is a ‘passive’ defence type injury?
- Victim raises arms and legs for protection
- Sliced, shelved often with skin flaps over backs of hands and forearms
What is an ‘active’ type defence injury?
- Victim reaches out to try and grab the weapon
- Sliced shelved incised wounds on palmer aspect of hands and web spaces between fingers – particularly between thumb and index finger
How can we identify self inflicted injuries?
- Commonly sharp force injuries
- Usually wrists/forearms, chest and abdomen
- Parallel, multiple and tentative incisions
What do consequences of injury depend upon?
- Type of mechanical injury: blunt, sharp etc
- Nature of target issue: head, abdo, fat
- Force involved: kicking, stamping, fall from height
- Number of impacts
What are some types of skull fracture?
Aetiology of sudden sub-arach haemorrhage?
- Due to rapid rotational movement of head, usually as the result of a single punch to jaw/ upper part of neck or side of head
- Sudden unexpected twisting movement
What does diffuse axonal injury mean?
- Immediate and prolonged coma with no apparent mass lesion or metabolic abnormality
What does traumatic axonal injury mean?
- This is a pathological term
- Damaged axons due to trauma
Identify some injuries that can occur post mortem?
- Animal predation
- Insect predation
